Estrogen regulation of yolk and non-yolk protein synthesis in the avian liver. An immunocytochemical study.
The effects of acute and chronic estrogen treatment on two egg yolk proteins, vitellogenin and apoVLDL-II, and two non-yolk proteins, ovalbumin and apoA-I, were studied by immunocytochemical techniques. Three groups of cockerels received either no treatment, or a single injection of diethylstilbestrol (DES, 2.5 mg) (acute stimulation) 24 h before killing, or 14 daily injections of 2.5 mg DES (chronic stimulation) before killing. The animals were killed at 4 weeks of age and their livers examined with respect to the distribution of the four different proteins by the indirect immunoperoxidase method. Vitellogenin was undetectable in the untreated cockerel liver. A single injection of DES resulted in the appearance of the protein in approximately 10%-15% of the hepatocytes. Chronic DES stimulation increased the number of positive cells to about 20%. In contrast, apoVLDL-II was present in 1%-2% of the hepatocytes in untreated animals. It was detected in an increased proportion (20%-25%) of cells after a single dose of DES. After chronic estrogen treatment, there was a very marked increase in the number of positive cells (less than 90%). Ovalbumin was undetectable in untreated cockerel liver, while apoA-I was detected in an extremely low proportion of cells (0.005%-0.01%). Neither ovalbumin nor apoA-I distribution seemed to be affected by a single dose of DES. However, chronic DES treatment resulted in the appearance of ovalbumin-containing cells (approximately 0.02%) and a marked increase in the number of cells containing apoA-I (10%-15%).
D000818:Animals; D016632:Apolipoprotein A-I; D001053:Apolipoproteins / Q000096:biosynthesis*; D002645:Chickens; D004054:Diethylstilbestrol / Q000494:pharmacology*; D004527:Egg Proteins / Q000096:biosynthesis*; D007124:Immunoenzyme Techniques; D008079:Lipoproteins, VLDL / Q000096:biosynthesis*; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010047:Ovalbumin / Q000096:biosynthesis; D014819:Vitellogenins / Q000096:biosynthesis
D016632:Apolipoprotein A-I; D001053:Apolipoproteins; D004527:Egg Proteins; D008079:Lipoproteins, VLDL; D014819:Vitellogenins; C027610:apolipoprotein VLDL II; D004054:Diethylstilbestrol; D010047:Ovalbumin